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Home , Egg, Egg incubation

B-6092 5-00 Incubating and Hatching Incubating and Hatching Eggs A. Lee Cartwright*

ggs of exotic and common Most eggs are laid by mid-morning. Eggs Echickens require a standard measure should be collected several times a day to of care in storage and incubation to reduce the amount of time eggs remain in the ensure a successful hatch. Environmental . This practice decreases the number of conditions, handling, sanitation and record cracked and soiled eggs and also prevents keeping can impact the success of incubating premature incubation. begin to and hatching eggs. prematurely develop at temperatures above 72 degrees F. Starting and stopping Fertile Quality development by repeatedly changing tem- peratures increases embryo death. Frequent From the smallest canary eggs to the collection and proper storage delays embryo largest eggs, high quality fertile eggs development until can begin. should always be considered rare and fragile. To successfully hatch eggs, begin with fresh, clean, fertile eggs. Storing Fertile Eggs Eggs can be produced “on site” or pur- Fertile eggs are alive. Each egg contains a chased from many sources. Commercial living cell mass that develops into an em- will ensure good fertility, but often bryo, and finally into a chick. Each incidence will not ship small quantities of eggs. of improper handling reduces the probability of a successful hatch. Fertile eggs usually are Eggs easily transmit contagious diseases gathered over a period of time before an between flocks. Therefore, to ensure adequate number of eggs can accumulate for protection from such diseases, purchase incubation, or until the incubator is available eggs from only National Improve- for a new set of eggs. These normal situations ment Plan (NPIP) or equivalent surveyed require that, before incubation, eggs must be facilities. Every egg producer should be stored properly to ensure hatchability. NPIP tested; further information can be obtained from Texas A&M University NPIP Cleaning and culling—Cracked, poorly at (979) 845-4186. shaped, soiled and unusually large or small eggs should not be incubated. These eggs If eggs are purchased by mail order, it is rarely hatch and they increase the probability important to ensure that the eggs receive of introducing infection into the incubator. proper care in transit. Extremes of tempera- ture and poor handling can destroy prospects Eggs should not be washed. Washing or for a good hatch. wiping with a damp cloth removes a protec- tive layer that coats the egg. Soiled eggs If fertile eggs are produced “on site” at the should be cleaned by gently buffing the business location, the breeding stock must be soiled area with fine sandpaper. Washing maintained and supported for maximum eggs transfers disease infection agents from health and fertility. Basic egg production is the surface to the inside of the eggs. severely affected by day length and lighting control. Egg quality and embryo livability are If an egg is washed, it should be washed affected by hen and sire age, health, nutri- briefly in 110-degree F water that contains a tion, cock/hen ratio, breeder genetics, and commercial egg sanitizer. Washing an egg in other factors that can stress birds such as the water that is cooler than the egg itself causes weather. Keeping more than four females per egg contents to contract. Contraction of egg male can reduce fertility in some settings. contents draws water into the egg through Inbreeding, the mating of closely related pores in the shell. This water carries infecting males and females, might decrease fertility of microorganisms into the egg. eggs and increase embryo mortality. Hatch- General care—After clean and undam- ability of eggs is severely harmed by inbreed- aged eggs have been selected for incubation, ing, age and poor health. use great care to prevent damage or contami- nation of the . This includes using * Extension Poultry Specialist, The Texas A&M Univer- frequent hand washing as a barrier to micro- sity System. bial contamination. Storage time—Ideally, eggs should be set humidity in an incubator. Relative humidity in the incubator as soon after gathering as is expressed as a percentage while wet bulb possible to maintain egg quality. If eggs are temperature is expressed as degrees. to be stored before incubation, the best A wet bulb thermometer can be purchased hatchability occurs when eggs are stored for or made from a common dry thermometer. less than 7 days from the time they were laid. Knowing how to make a wet bulb thermom- However, some species are more sensitive to eter helps to understand how it works. A storage than other species. Hatchability thermometer, a shoelace (approximately a 6- decreases rapidly in eggs held in storage for inch long piece) and a short piece of dental more than 10 days. Storing eggs longer than floss are needed. First, stick the bulb end of 2 weeks also can extend the normal incuba- the thermometer about 1 inch into the hollow tion time as much as 1 day. of the shoelace. Next, tie a piece of dental Temperature and humidity during floss around both the shoelace and thermom- storage—Fertile eggs should be stored at a eter directly above the bulb. This is to keep dry bulb, normal temperature between 55 the shoelace from sliding off. Place the degrees F and 65 degrees F, or 13 degrees C opposite end of the shoelace directly in a pan and 18 degrees C. Embryos will begin to of water. If the water is the same temperature develop abnormally, weaken and die if the as the air temperature, the reading on the temperature is too high. A low temperature thermometer is the wet bulb temperature. also causes high embryo mortality. Storage The temperature reading of the wet bulb will temperature should never exceed 72 degrees be less than a dry thermometer because F (22 degrees C) and never go below 46 evaporation of water cools the thermometer. degrees F (8 degrees C). Egg storage at room However, the reading also will be influ- temperature or at normal refrigerator tem- enced by the relative humidity of the air. The peratures (32 degrees F to 40 degrees F) is not wet bulb reading is used as an index of acceptable because hatchability decreases. relative humidity but is not numerically A refrigerator can be used to store eggs if equal to the relative humidity value. The wet the temperature is properly adjusted to the bulb temperature will change at different dry recommended temperatures. Eggs should be bulb temperatures even as the relative stored in a refrigerator dedicated to egg humidity remains constant. So, the appropri- storage because these temperatures are not ate wet bulb temperature that is to be main- low enough to safely store food. Storage tained must be known for each dry bulb temperature should be reduced to 50 degrees temperature that occurs during storage. F or 55 degrees F if eggs must be stored more Relative humidity in the storage room than 2 weeks. should be approximately 70 percent to 80 Holding eggs for more than 10 days percent (wet bulb temperature of 50 degrees reduces hatchability. However, chukar and F to 60 degrees F). Condensation forms on eggs are an exception. Chukar eggs eggshells exposed to excessive humidity. have been stored 3 weeks to 4 weeks without Condensation on the can clog pores appreciable loss in hatchability. and, like washing eggs, provides a vehicle for A good storage area also requires stable contamination. Suffocation or contamination humidity. Two methods, wet bulb tempera- of the embryo can result. Excessive amounts ture and relative humidity, are measures of of water evaporate from the egg if humidity humidity. These two methods should not be is too low, which also causes embryo death. confused; whenever humidity measures are To increase the humidity, a pan of water can discussed, know which method is referenced. be placed in the storage room. If the incuba- tor temperature is correct, the only factor Relative humidity is the water vapor in governing humidity is the surface area of the air expressed as a percentage of the water inside the incubator or storage unit. greatest amount of water vapor possible at Avoid drafts during storage that can dry eggs that temperature. The amounts of water even when humidity levels are within vapor that air can contain are different at appropriate levels. different temperatures. To measure relative humidity, expensive equipment or a compli- Hatchability is best maintained by storing cated procedure is required. However, the eggs with the small end down in sealed, wet bulb temperature is easily measured and airtight plastic bags. The bags help keep the is the method usually used to measure eggs clean and prevent moisture loss.

2 Positioning and turning eggs during storage—Eggs that will be stored for less Egg Storage Reminders than 10 days before incubation should be ✰ Store less than 10 days. placed on egg flats or in egg cartons with ✰ Maintain temperature between 55 degrees to 65 degrees F. the large end up. Eggs do not need to be ✰ Keep relative humidity at 75 percent (50 to 60 degrees F wet turned from side to side during storage if bulb temperature). they are incubated within the week the ✰ eggs are laid. If the eggs are not sealed in a Turn eggs stored more than a week. plastic bag, cover them with a loose fitting ✰ Handle the eggs with care! material to prevent debris or dust from soiling the eggs. Eggs stored for more than 10 days should Consider the differences between forced- be tilted from side to side over a 90-degree draft and still air incubators before choosing a angle once or twice a day to assure optimal system to use. Forced-draft incubators main- hatching success rates. To turn eggs during tain more consistent temperature and humid- the holding period, place a 6-inch block ity levels throughout the incubator, and under one end of the carton (or flat) holding recover temperature and humidity to regu- the eggs to produce a 45-degree angle against lated levels faster when doors are opened the floor. The next day, remove the block and during the incubation period. In still air place it under the opposite end of the carton. incubators, wet bulb readings are misleading Turning eggs prevents some hatchability loss and a water reservoir with a large surface that can occur during long-term storage. area is needed. Temperatures in still air incu- bators must be monitored at the level of the Incubation eggs since temperature can vary considerably between locations within a still air incubator. When an adequate number of eggs are Forced-draft incubators are preferred. collected, move eggs from storage to incuba- tion. The temperature and humidity of the room housing the incubator should be controlled Incubators—Incubators of several types and stable. Place the incubator in a stable and capacities with adapters for eggs from environment, free of drafts and away from different species are available. Basically, an direct sunlight. incubator is a box that holds and rotates eggs while maintaining appropriate temperature, Locate the incubator and hatcher away humidity and oxygen levels. A well-designed from growing facilities. The equipment and incubator should maintain temperature newly hatched chicks can be contaminated by within 1/4 degree F and humidity within 1 older birds, and the dust that accompanies degree F wet bulb temperature. growing birds. Keep foot traffic to a mini- mum; personnel should limit trips between Several features are standard in popular or the growing area and the incubation area as larger incubator models. Automatic turners much as possible. Do this by attending to the that turn eggs at least once every 2 hours to 4 incubator and hatchlings before maintaining hours are recommended. Humidifiers are of other areas. several types. Some are actuated by wet bulb systems while others are designed to main- Chicks can be hatched in the same unit in tain humidity by a simple water reservoir which they were incubated. However, hatch- surface area system. Either of these systems ing creates large amounts of dust and down. can be used effectively. Temperature can be Hatching in a separate unit prevents contami- controlled by the older wafer system or by nating and soiling the incubator. Temperature newer microprocessor systems. Whatever the and humidity also can be managed more system chosen, an incubator with a backup effectively if separate units are used for controller set at less than 102 degrees F can incubation and hatching. It is best to keep save the hatch if the primary temperature hatchers in a separate room from the incuba- controller ever malfunctions. Remember that tor. The incubator and the hatchers should be temperature, humidity, ventilation and constructed and coated with material that is turning are the important factors during easily sanitized. The incubation and hatcher incubation. rooms should also be constructed or coated with impermeable material that can be easily washed and sanitized.

3 Two days before incubation—Prepare does not exceed 102 degrees F, the hatch and adjust the incubator 2 days or 3 days should not be harmed. before setting the eggs. Ensure that the The small end of the egg should be lower incubator is clean and sanitized. Make proper than the large end of the egg when set in the adjustments to the temperature and humidity incubator. An embryo orients during incuba- at this time. Adjustments made while eggs tion so that the head develops toward the are set can either lengthen or shorten the large end of the egg where the air cell is time of hatch, or kill or damage the embryos. located. A chick’s head can orient away from If the incubator has an automatic turner, the air cell of the egg if the small end is make sure the turner functions properly. The higher than the large end during incubation. temperature in the room where the incubator An embryo oriented in the wrong direction is located should also be controlled during will not hatch. this time. Do not set the eggs until tempera- Set stage—The ‘set stage’ refers to the ture and humidity are correct and stable. days of incubation prior to the final 2 days or Cleaning and fumigation—Microbial 3 days before a hatch. Different species have infection in an incubator can significantly different incubation periods (Table 1). reduce hatchability of eggs. Cleaning proce- Incubating different species at the same time dures and disinfecting equipment should be in the same incubator is not recommended, part of standard operating procedures. especially if the incubator is also used as a Incubators, hatchers and the racks should be hatcher. disinfected with quaternary ammonia or Birds in the wild frequently turn their eggs commercial disinfectant after each hatch. in the nest. Similarly, turning eggs during Some larger businesses fumigate incuba- incubation prevents embryo death and tors before setting eggs. Occasionally the unhealthy hatches. Eggs must be turned at incubators are fumigated briefly with lower least five times within a 24-hour period. concentrations of the fumigant while eggs are Turning more frequently is better; once per in the incubator. Do not fumigate eggs after hour is best. This turning schedule must be the first day of incubation. Embryos are maintained even through weekends. An sensitive to fumigation between 2 days and 5 automatic turner is recommended. If the days of incubation. When eggs are fumigated incubator is equipped with an automatic at set, exposure of the eggs should be limited. turner, eggs will be turned at least every few Only trained individuals should use these hours. techniques. Temperature, humidity and ventilation of The day eggs are set—Remove eggs from incubator (set stage)—Temperature in the storage and allow them to warm to room incubator should be 99.5 degrees F to 100 temperature for 4 hours to 8 hours before degrees F (37.5 degrees C). If the temperature setting in the incubator. Cold eggs placed deviates more than 1/2 degree from 100 into a warm, humid incubator will become degrees F, a poor hatch is likely. Temperature covered in condensation that will increase should be checked at least twice a day. the possibility of egg contamination. Ensure Relative humidity should be set at 86 that proper records are maintained so that degrees F to 88 degrees F (30 degrees C) wet eggs are turned a minimum of three to five bulb temperature. Humidity should not times in a 24-hour period. Failure to turn fluctuate more than 1 wet bulb degree. If the eggs adequately results in embryo death. Use incubator uses a passive humidity control of an automatic turner considerably simpli- system, water should be added daily to the fies the work and decreases human error water pan or trough to ensure correct humid- during the incubation process. ity levels. Once eggs are in the incubator, do not If the humidity in the incubator is too low adjust the temperature or humidity for a few or too high, the hatch will fail. When humid- hours unless the temperature exceeds 102 ity is too low during incubation, the air cell degrees F. After 4 hours, make proper adjust- will be too large at the time of hatch. The ments. The final temperature should vary contents of the egg will be too thick and only 1/2 degree above or below 99.5 degrees F. sticky for the chick to turn. The membranes The temperature of incubators without will be too tough to break. The navel will not circulating fans fluctuates more than incuba- close properly. tors with circulating fans. If the temperature

4 Table 1. Total incubation time to hatch, time for transfer to hatcher, and dry and wet bulb temperatures for common birds. Common Name Incubation Conditions Hatcher Conditions Period Dry Bulb Wet Bulb Transfer Dry Bulb Wet Bulb (days) (° F) (° F) at day (° F) (° F) Canary 13-14 100.5 86-88 11 99 90-94 21 99.5 86 18 98.5 90-94 Cockatiel 18-20 99.5 86-88 15-18 99 90-94 (various) 22-30 99.5 86-88 20-27 99 90-94 (Sun) 28 99.5 86-88 25 99 90-94 Conure (various) 21-30 99.5 86-88 18-27 99 90-94 Dove 14 99.5 86 12 98.5 90-94 (common) 28 99.5 86-88 25 98.5 90-94 35-37 99.5 86-88 31-33 98.5 90-94 (Zebra) 14 99.5 86-88 12 99 90-94 Domestic 30 99.5 88 27 98.5 90-94 Geese (various) 22-30 99.5 88 20-27 98.5 90-94 24-25 99.5 84-86 22 99 90-94 Guinea 28 99.5 84-86 25 98.5 90-94 Lovebird (various) 22-25 99.5 86-88 20-22 99 90-94 Macaw (various) 26-28 99.5 86-88 23-25 99 90-94 Mynah 14 100.5 86-88 12 99 90-94 Parakeet (various) 18-26 99.5 86-88 15-23 99 90-94 Budgerigar 18 99.5 86-88 15 99 90-94 (various) 18-28 99.5 86-88 15-25 99 90-94 Parrot (African Grey) 28 99.5 86-88 25 99 90-94 Chukar 23-24 99.5 88 20 99 90-94 Peafowl 28-29 99.5 86-88 25-26 98.5 90-94 Ptarmigan 21-23 99.5 86-88 18-20 99 90-94 Raven 20-21 99.5 86-88 17-18 99 90-94 Ring-neck 24-25 99.5 86-88 21 99 92-95 Pheasant (various) 22-28 99.5 86-88 20-25 99 92-95 Pigeon 17-19 100.5 88 14 99 92-95 Bobwhite Quail 23 99.5 84-86 21 99 90-94 17-18 99.5 86-88 15 99 90-94 (various) 33-37 99.5 86-88 30-33 99 90-94 Turkey 28 99.5 84-86 25 98.5 90-94 49-50 97.5 70-75 47 97.5 90 Ostrich 42 97.5 70-75 39 97.5 90 36-42 97.5 80 97.5 90 1 This period is the entire incubation time until hatch that includes 3 days in the hatcher. Ventilation should be increased half way through the incubation period.

5 If the humidity in the incubator is too high Candling during incubation, too little water will All incubated eggs will not hatch. It is evaporate from the egg. The air cell will be probable that only 90 percent or less of too small for the chick to reach during the incubated eggs are fertile. Removal of eggs hatching process. The chick will either drown that can be identified as infertile or dead or the chick will be too swollen with water to eliminates possible sources of contamination turn itself within the egg. The sac will from the incubator. Candling can be used to also be too large for the navel to completely identify some of these eggs. close. These problems will cause the hatch to fail. Shining a light through the egg to observe embryo development is called “candling.” The air cell of the egg should become White or pale eggs are more easily candled larger as incubation progresses. Chicken eggs than dark or speckled eggs. Many people use will lose 12 percent to 14 percent of their total small flashlights with lenses the size of a weight by evaporation during incubation. nickel that can be focused to candle eggs. The growth of this air cell is a balance Excellent candlers also can be purchased at a between temperature and humidity during reasonable cost. Simple candling devices can the incubation. Racks of eggs can be weighed be made by inserting a light into a container during incubation to detect problems with and cutting a small hole to emit light, or by humidity and evaporative loss before a hatch taping a cone formed from several thick- is destroyed. nesses of paper over the lens of a bright light The chick embryo uses oxygen and projector. The hole that allows light to pass produces carbon dioxide. This gas exchange from the tip of the cone should be the size of is insignificant during the early period of a dime or quarter (depending upon the size incubation or when a small number of eggs of the egg). are incubated. However, recommendations of In a dark room, hold the egg to the light of the incubator manufacturer should be the candler to observe the contents of the followed to assure that adequate oxygen is egg. Cooling that occurs for short periods available to the developing chicks. Near the (less than 10 minutes) during careful exami- end of the incubation period, the eggs are nation of eggs does not harm the develop- nearly filled with the embryo. An incubator ment of the embryo. However, limit the filled with eggs contains a large mass exposure of the egg to the hot light source. that requires large amounts of oxygen. Even a brief period at 104 degrees F kills all Adequate ventilation is needed during the embryos. end of the incubation period. Particular attention should be focused on air vent The presence of embryos can be confirmed settings, and wet and dry bulb temperatures easily after 8 days to 12 days of incubation. during the last third of incubation. The embryo is located in the large end of the egg, where blood vessels radiate under the Record keeping—Keep a daily record of surface of the shell. The embryo appears as a the incubator environment (Appendix A). dark spot that becomes larger as incubation This sample record is designed for use with progresses. Eventually only a dark mass and eggs that hatch after 21 days of incubation. the air cell are seen. An infertile or Record keeping can be used to detect mal- unincubated egg brightly transmits light in functions before a disaster develops. Also, comparison. Remove infertile or nongrowing records of fertility and embryo deaths alert eggs from the incubator. If questions arise the manager to production, storage, about candling, contact someone with or incubator problems so that adjustments experience for advice. can be corrected before major losses occur. Dead embryos will sometimes appear as a Proper records call attention to deviations ring or smear of blood in the egg or a dark that could destroy a producer’s profits. A 5 spot dried to the inside of the shell. The percent loss of hatchability can go unnoticed. living embryo will appear as a dark spot in However, a 5 percent loss is 100 percent the large end of the egg surrounded by a profit, and conditions that cause a 5 percent faint outline of blood vessels. The blood reduction in hatchability also contribute to vessels will appear firm and distinct. After health problems in successfully hatched embryo death, the embryo no longer grows chicks. and the blood system fades.

6 Retain records of egg infertility or embryo death. Some mortality can be expected, Incubation Reminders ✰ however, unusual occurrences of mortality or Locate the incubator in a room with a constant temperature, certain characteristics of the mortality can be away from drafts and direct sunlight. indicators of practices that can be corrected ✰ Sanitize the incubator. to improve hatchability. ✰ Ensure that the humidifier and wet bulb wick are in working order. Hatch Stage ✰ Wash hands before touching eggs. Keep germs, dirt and oil The hatch stage refers to the final 2 days to away from incubating eggs. 3 days of incubation. Chicks hatch out of the ✰ Only incubate egg species with similar incubation lengths at shell during this stage. Do not turn the eggs the same time in one incubator. during the last 3 days to 4 days of incubation. ✰ The small end of the egg should not be higher than the large Transfer eggs to a dedicated hatcher at this end. time. If a hatcher is unavailable, remove the ✰ eggs from the turner and lay the eggs in the Keep a daily record of incubator data. hatching basket or place on cloth or rough ✰ Check temperature daily and keep it at 99.5 degrees F to 100 paper (not newspaper) in the incubator. degrees F. Make sure that the paper does not obstruct ✰ Verify that the water trough is full and humidity measures airflow, contact the water, or contact the 86 degrees F to 88 degrees F wet bulb. heating element. Temperature should remain ✰ Turn eggs at least five times a day until the last 3 days before at 99.5 degrees F and increase the humidity hatch. to at least 90 degrees F wet bulb. Humidity ✰ can be increased by adding either a wet Increase ventilation during the last one-third of the incubation or wet paper towels to increase the period. evaporative surface in the incubator. The ✰ Do not turn for the final 3 days. Provide a cloth or rough chicks should start to pip within a day of the paper surface upon which chicks can walk. incubation period listed for the species in ✰ Increase wet bulb to 90 degrees F in the hatcher. Table 1. When Chicks Hatch should never be used for breeding purposes The hatching process requires great because these traits could be transmitted exertion by the chick. The chick progresses genetically to their young. through periods of activity followed by lengthy periods of rest. The entire hatching process requires 10 hours to 20 hours. Do not Embryo Mortality (Death) be concerned about the time a specific chick Unsuccessful hatches can be caused by requires to hatch unless the process exceeds infertile eggs or embryo mortality. Each of 20 hours. these conditions can be diagnosed after Once chicks successfully leave the shell candling and after hatch. Examine eggs that they should remain in the incubator until do not hatch to estimate whether infertility or their are dry. Ventilation should be embryo death is the basis for hatch failure. increased. When more than 90 percent of the Keep records of the time of embryo death; chicks are dry they should be removed from such records can suggest changes in hus- the hatcher. Excessive time in the incubator bandry that can increase profitability. A can dehydrate chicks. Remove chicks to a sample record form for hatch and fertility warm brooder and provide them with water failures is in Appendix B. and feed. Embryo death predominately occurs at Eggs that remain unhatched for 1 day two periods during incubation: within the beyond the predicted incubation period first 3 days of incubation and within the last should be discarded. Attempts to help a 3 days immediately before a hatch. chick free itself from the shell often are Early embryo death occurs during forma- unsuccessful. Chicks too weak to hatch tion of embryonic organs. Of all the eggs themselves usually do not live. If they live, determined to be fertile by candling at one- they usually will not thrive. Dispose of weak third of incubation, 88 percent to 93 percent or deformed chicks humanely. These chicks should continue to develop.

7 Death immediately before a hatch occurs , wings and legs for proper form. All during the transition between abnormalities should be recorded and living in an egg to living on the analyzed to determine if hatch failure re- outside. The chick can have diffi- sulted from fertility or environmental prob- culty positioning for pipping, lems that can be corrected by changing absorbing the , or management procedures. Nutrition can be a changing to breathing air. factor in fertility and hatchability problems, Sometimes humidity control as recognized by the National Research can be implicated in some of Council (Appendix C). these problems. An overall hatch Examine the eggs that fail to hatch by of more than 85 percent to 90 removing the top of the egg at the large end. percent can be achieved. Carefully examine the contents and classify Collect and examine all unhatched infertile or dead embryos using the designa- eggs to determine the cause of hatch tions listed in Table 2. failure. An appropriately developed Use the “Hatchability and Mortality chick within the egg will show Record” (Appendix B) to calculate the certain characteristics. Normally percentage fertility, percentage hatchability the head is under the right wing. and percentage of total eggs hatched. These The air cell will be large enough to numbers will help in evaluating hatch allow the chick to position correctly efficiency. Any change in these figures, or a for hatching. The shell membranes change in the distribution in mortality should not dry to the chick during hatch. records are early warnings to correct small Note any dryness. Note the condition of the problems before they become serious.

Table 2. Incubating and Hatching Egg and Chick Classification. Culled eggs Cracked, misshapen or otherwise not likely to hatch. Infertile eggs Determined to have no germ. Originally infertile. These eggs are clear during candling and show no evidence of blood or embryo development. Early dead Embryos died during the first quarter of incubation. Some of these can be detected and removed during candling. These eggs would be fertile and could show a dead early embryo, show no development, development but no blood, or a blood ring. Middle dead Embryos died after the “early” period but before transfer. Late dead Embryos died during the hatch phase of incubation. Malformed Embryos that have an obvious deformity. Malpositioned Embryos not positioned correctly for hatching. Live pips Chicks that have pipped and are living, but not hatched. Dead pips Pipped chicks that died but are not malformed or malpositioned. Rots Infected or contaminated eggs. Culled chicks Chicks that hatched but are unsound. Good chicks Good quality, healthy normal chicks.

Table 3. Possible Causes of Hatching Problems Observation Possible Causes Eggs Exploding Dirty eggs Improperly cleaned eggs Dirty incubator No embryonic development Infertile egg Rough handling of eggs Incubation temperature too high Incubation temperature too low Eggs stored too long 8 Table 3. Possible Causes of Hatching Problems (continued) Observation Possible Causes No embryonic development Eggs stored improperly Breeders stressed Too many hens per rooster Old or unhealthy hens or males Inbreeding Disease Bloodring Old eggs Early dead Incubation temperature too high Incubation temperature too low Dead embryos, second week Incubation temperature too high Incubation temperature too low Electric power failure Eggs not turned Inbreeding Infection Poor nutrition of breeders Air cell too small Humidity too high Air cell too large Humidity too low Chicks hatch early Small eggs Dry chicks Temperature too high Bloody navels Humidity too low Chicks too small Chicks hatch late Large eggs Old eggs Temperature too low Humidity too high Chicks dead after pipping shell Eggs not turned first 2 weeks Thin-shelled eggs Incorrect temperature during incubation Temperature too high during incubation Humidity too high during incubation Humidity too low during incubation Infection, disease Unhealed navel Temperature too low during incubation Mushy or water-logged chicks Wide temperature variation in incubator Humidity too high during incubation Poor ventilation Malformed legs and toes Improper temperature during incubation Improper humidity during incubation Legs also may be harmed by hatching or holding chicks on a smooth surface Weak chicks Temperature too high or low Old eggs Poor ventilation Gasping chicks Disease Bronchitis Newcastle disease Malpositions Temperature too high or low Turning inadequate Large end of egg not up when set Old or poorly handled eggs Poor breeder nutrition

9 APPENDIX A: INCUBATOR DATA CHART

Turner Works1 Temperature Wet Water Day # Date 1 2 3 Room Incubator Bulb Checked Candling Remarks 1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19 XXX XXX XXX

20 XXX XXX XXX

21 XXX XXX XXX

This record is important. Keeping data will help prevent problems from developing during incubation. 1 Check the turner three times each day except days 19 through 21. Eggs are not turned on these days.

10 3 Total 2 Hatch 1 // // // // // // // // // // // // Early Middle Late Malposition Live/Dead Rots Cull Good Fertility APPENDIX B: Hatchability and Mortality Record APPENDIX B: Hatchability and Mortality Infertile Set Candling Eggs Dead Malformed/ Pips Chicks Percentage ID # Date Date Culled Fertility (%) = (Fertile Eggs/Eggs Set) x 100%. Hatchability (%) = (Good Chicks Hatched/Fertile Eggs) x 100%. Eggs Hatched (%) = (Good Chicks Hatched/Eggs Set) x 100%. Total This record is important. Keeping data will help identify problems with husbandry and incubation. with data will help identify problems is important. Keeping This record 1 2 3

11 Appendix C: Signs of Deficiency in the Embryo

Nutrient: Deficiency Signs:

Vitamin A Death at about 48 hours of incubation from failure to develop the circulatory system; abnormali- ties of kidneys, eyes and skeleton

Vitamin D Death at about 18 or 19 days of incubation, with malpositions, soft bones, and with a defective upper mandible prominent.

Vitamin E Early death at about 84 to 96 hours of incubation, with hemorrhaging and circulatory failure (implicated with selenium).

Vitamin K No physical deformities from a simple deficiency, nor can they be provoked by antivitamins, but mortality occurs between 18 days and hatching, with variable hemorrhaging.

Thiamin High embryonic mortality during emergence but no obvious symptoms other than polyneuritis in those that survive.

Riboflavin (Vitamin B2) Mortality peaks at 60 hours, 14 days, and 20 days of incubation, with peaks prominent early as deficiency becomes severe. Altered limb and mandible development, dwarfism and clubbing of down are defects expressed by embryo.

Niacin Embryo readily synthesizes sufficient niacin from tryptophan. Various bone and beak malforma- tions occur when certain antagonists are administered during incubation.

Biotin High death rate at 19 days to 21 days of incubation, parrot beak, chondrodystrophy, several skeletal deformities and webbing between the toes. Perosis.

Pantothenic acid Deaths appear around 14 days of incubation, although marginal levels may delay problems until emergence. Variable subcutaneous hemorrhaging and edema; wirey down in poults.

Pyridoxine Early embryonic mortality based on antivitamin use.

Folic acid Mortality at about 20 days of incubation. The dead generally appear normal, but many have bent tibiotarsus, syndactyly and mandible malformations. In poults, mortality at 26 days to 28 days of incubation with abnormalities of extremities and circulatory system.

Vitamin B12 Mortality at about 20 days of incubation, with atrophy of legs, edema, hemorrhaging, fatty organs, and head between thighs malposition.

Manganese Deaths peak prior to emergence. Chondrodystrophy, dwarfism, long bone shortening, head malformations, edema, and abnormal feathering are prominent. Perosis.

Zinc Deaths prior to emergence, and the appearance of rumplessness, depletion of vertebral column, eyes underdeveloped and limbs missing.

Copper Deaths at early blood stage with no malformations.

Iodine Prolongation of hatching time, reduced thyroid size, and incomplete abdominal closure.

Iron Low hematocrit; low blood hemoglobin; poor extra-embryonic circulation in candled eggs.

Selenium High incidence of dead embryos early in incubation.

12 Resources Publications Mullin, J.M. and P.M. Boehmer. Gamebird Propagation. Wildlife Harvest Publications, Inc., 2000. Hatching Manual. Lyon Electric Company, Inc., 1988. Stromberg, Janet. A Guide to Better Hatching. Stromberg Publishing Company, 1975. Circular 530, “Incubating Eggs of Domestic Birds.” Cooperative Extension Service, Clemson University. B-1123, “Care, Management, Propagation - Japanese Quail (Coturnix).” Texas Agricul- tural Extension Service. Leaflet No. 519, “Raising Guinea .” U.S. Department of Agriculture, U.S. Gov- ernment Printing Office. Circular 514, “Raising Bobwhite Quail for Commercial Use.” Cooperative Extension Service, Clemson University. Leaflet 21046, “Raising Game Birds.” Division of Agricultural Sciences, University of California. Leaflet 21321, “Raising Chukar .” Department of Avian Sciences, University of California. Bulletin 878, “Game Bird Production and Health.” The Cooperative Extension Service, University of Georgia. Wall charts Cherms, F.L. “Embryonic Mortality of Turkey Wall Chart,” Nicholas Turkey Breeding Farms, Inc., Sonoma, Calif. “Embryo Development Chart,” Jamesway Incubator Co., Monroe, N.C. Poster 21559, “The Australian Emu: Embryonic Development,” ANR Communication Services, University of California. http://anrcatalog.ucdavis.edu. Poster 3321, “Development of the Pheasant Embryo,” ANR Communication Services, University of California. http://anrcatalog.ucdavis.edu. Video V86-W, “Hatching Egg Breakout Video,” ANR Communication Services, University of California. http://anrcatalog.ucdavis.edu. For more information about sources and suppliers of incubators and supple- mental equipment, contact the local office of the Texas Agricultural Extension Service or contact Lee Cartwright in the Poultry Science Department, 107 Kleberg Center, 2472 TAMU, College Station, TX 77843-2472, telephone (979) 845-4319, fax (979) 845-1921, e-mail [email protected]

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